Otoscopes are hand-held instruments that are commonly known in the medical diagnostic instrument field by practitioners and health care providers primarily for examining the ear, including the tympanic membrane, of a patient.
A typical otoscope is capable of being held in the hand of a practitioner and includes an instrument head having a distal frusto-conical insertion portion that permits overlying attachment of a disposable speculum tip. The disposable speculum tip is also preferably designed with a frusto-conical configuration to permit insertion to only an appropriate distance into the ear canal of the patient. Commonly, a ringlet of optical fibers encircles the tip opening of the insertion portion so as not impede with the user's visualization of the target, the fibers extending from a contained light source, such as a miniature incandescent lamp or bulb, that is housed within the instrument handle or a neck portion of the instrument head. The target (e.g., the tympanic membrane) is then viewed via a lens located in the proximal end of the instrument head, the lens being aligned optically with the distal tip opening of the insertion portion to permit user viewing. Often, the lens magnifies the view of the target.
Alternatively, a video camera or at least one solid state imaging element, such as a CCD or CMOS-based imager, can be used to view the target in lieu of the lens, the image as processed being transmitted to a video monitor for display. In addition, the instrument head can include a receiving port for a pneumatic bulb, permitting insufflation (e.g., pneumatic otoscopy). These devices can also be used, in some instances, for examining the nose and throat in addition to the ear and ear canal, as well as to provide a general illumination and magnification system.
There are a number of perceived needs in the field currently. When considering the basic functions of the otoscope; e.g., visualization of the tympanic membrane, there have been expressed needs to increase the field of view and to provide greater magnification thereof, in addition to eye relief. Eye relief is practically defined as the distance between the most proximal optic of the instrument (e.g. the optic closest to the practitioner's eye) and the practitioner/user's eye when the full field is viewed. Magnification and eye relief are interrelated such that having an image overly magnified will bring the image “closer” to the eye of the practitioner, etc. Current otoscopes, due to the tortuous construction of the ear canal and the lenses that are used therein, cannot fit the entire tympanic membrane into the field of view.
To provide all of these noted improvements, in general, requires a tradeoff in depth of field, since optically all of the above factors are related. For example, the consequence of a depth of field loss is that for some patients with either long or short ear canals (as compared to a so-called “standard” or nominal ear canal), the tympanic membrane would no longer be in focus. This lack of focus is a distinct disadvantage and would seriously impact the practitioner's ability to give proper care.
There is yet another need generally in the field to be able to perform different diagnostic procedures as part of a comprehensive otoscopic examination. This need places increasing demands and constraints upon releasably attached disposable speculum tips used with the apparatus, in order to maintain cleanliness and prevent cross-contamination. A brief list of the requirements that are attributed to these type of otoscope tips include the following:
i) to achieve the “best view” (e.g., straighten the ear canal walls, maximize clear aperture);
ii) to effectively transmit light to the tympanic membrane and to collect light transmitted back from the tympanic membrane in order to effectively permit viewing thereof;
iii) to provide an effective substantially fluid-tight seal with the ear as well as with the instrument head in order to permit insufflation (e.g., pneumatic otoscopy);
iv) to allow placement and use of certain instrumentation while viewing through the optics, for cerumen (ear wax) removal;
v) to permit stacking of the tips in a compact fashion to facilitate storage in a dispenser or work kit;
vi) to be adequately cost-effective terms of manufacture in order to permit the tips to be disposable or replaceable;
vii) to prevent cross contamination;
viii) to fit a variety of patients (e.g., different sizes)
ix) to minimize the risk of unsafe insertion into the typical ear; and;
x) to fit relevant otoscopes used.
To meet this fairly comprehensive list of requirements, it becomes clear that any presently known otoscope tip would either optimize for only one or two of the above attributes, or perform moderately on a few of them. As a result, there are shortcomings, particularly with regard to disposable speculum tip designs that are presently available.